The thermal softening has been recently demonstrated to directly depend also on the plastic strain other than depending on the temperature, so that the stress-strain curves of a metal at different constant temperatures are not proportional each other through a single, temperature-dependent scale factor. In this paper a considerable anticipation of the necking onset from static tests at increasing constant temperatures is highlighted for a stainless steel, which directly delivers further evidence that the thermal softening depends on both temperature and strain. Only in the post-necking ranges the strain seems to not influence the thermal softening anymore. Also, the variabilities of temperature and strain rate during dynamic strain histories are shown to further affect the necking onset, while an ideally constant high strain rate does not. The identification of the above features and their implementation in the thermal softening from static tests can also help in correctly assessing the strain rate sensitivity of materials from dynamic tests by Hopkinson bar, where the thermal and dynamical effects are intrinsically coupled to each other and a procedure for their separate assessment is not yet standardised.

Coupling of temperature and strain in thermal softening of a stainless steel at low and high strain rates

Mirone, Giuseppe
;
Barbagallo, Raffaele
2019-01-01

Abstract

The thermal softening has been recently demonstrated to directly depend also on the plastic strain other than depending on the temperature, so that the stress-strain curves of a metal at different constant temperatures are not proportional each other through a single, temperature-dependent scale factor. In this paper a considerable anticipation of the necking onset from static tests at increasing constant temperatures is highlighted for a stainless steel, which directly delivers further evidence that the thermal softening depends on both temperature and strain. Only in the post-necking ranges the strain seems to not influence the thermal softening anymore. Also, the variabilities of temperature and strain rate during dynamic strain histories are shown to further affect the necking onset, while an ideally constant high strain rate does not. The identification of the above features and their implementation in the thermal softening from static tests can also help in correctly assessing the strain rate sensitivity of materials from dynamic tests by Hopkinson bar, where the thermal and dynamical effects are intrinsically coupled to each other and a procedure for their separate assessment is not yet standardised.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11769/396984
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 4
  • ???jsp.display-item.citation.isi??? ND
social impact